1. Field of the Invention
The present invention relates to a control for controlling splitter section jaw clutch engagement during completion of a transmission shift, and in particular, to a control wherein a controller commands engagement of splitter jaw clutches during a compound transmission shift in a sequencewherein the splitter section is moved to and retained in neutral until the main section is sensed as being engaged. In the preferred embodiment, the splitter jaw clutch is a double sided jaw clutch manipulated by a three-position, ECU-controlled actuator and engagements are commanded only when transmission input shaft speed is or is expected to be within a predetermined offset of a true synchronous speed (IS=OS*GR.sub.T). The magnitude of the offset (i.e., the width of the "synchronous window") is, preferably, adaptively varied as a function of the rate of change of vehicle speed (d/dt(OS)) and of engine rotational speed (d/dt(ES)).
2. Description of the Prior Art
Compound manually shifted mechanical transmissions of the range, splitter and/or combined range/splitter type are in wide use in heavy-duty vehicles and are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,754,665; 5,272,929; 5,370,013 and 5,390,561, 5,546,823; 5,609,062 and 5,642,643, the disclosures of which are incorporated herein by reference. Typically, such transmissions include a main section shifted directly or remotely by a manual shift lever and one or more auxiliary sections connected in series therewith. The auxiliary sections most often were shifted by a slave actuator, usually pneumatically, hydraulically, mechanically and/or electrically operated, in response to manual operation of one or more master switches. Shift controls for such systems by be seen by reference to U.S. Pat. Nos. 4,455,883; 4,550,627; 4,899,607; 4,920,815; 4,974,468; 5,000,060; 5,272,931; 5,281,902; 5,222,404 and 5,350,561, the disclosures of which are incorporated herein by reference.
Fully or partially automated transmission systems wherein a microprocessor-based electronic control unit (ECU) receives input signals indicative of various system operating conditions and processes same according to logic rules to issue command output signals to one or more system actuators are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,593,580; 4,595,986; 4,850,236; 5,435,212; 5,582,069; 5,582,558; 5,620,392; 5,651,292 and 5,679,096; 5,682,790; the disclosures of which are incorporated herein by reference.